n.

a note that alternates rapidly with another note a semitone above it

同義詞：shake

the articulation of a consonant (especially the consonant `r') with a rapid flutter of the tongue against the palate or uvula

"he pronounced his R's with a distinct trill"

The trills of Toda
The trills of Toda
Tongue-tip trills and vocal-tract wall compliance
Aerodynamic characteristics of trills and phonological patterning
Effects of Rapid Broadband Trills on Responses to Song Overlapping in Nightingales
Contrast Maintenance of Taps and Trills in Dominican Spanish: Data and Analysis
On the production characteristics of apicoalveolar taps and trills
Reverberation of rapid and slow trills: implications for signal adaptations to long-range communication
Independent component analysis for automatic note extraction from musical trills.
Comparative Analysis of the Closed Quotient for Lip and Tongue Trills in Relation to the Sustained Vowel /epsilon/